/*
 * Copyright (C) 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.zxing.client.android;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.res.AssetFileDescriptor;
import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.Vibrator;
import android.preference.PreferenceManager;
import android.text.ClipboardManager;
import android.util.Log;
import android.util.TypedValue;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.Result;
import com.google.zxing.ResultMetadataType;
import com.google.zxing.ResultPoint;
import com.google.zxing.client.android.camera.CameraManager;
import com.google.zxing.client.android.history.HistoryManager;
import com.google.zxing.client.android.result.ResultButtonListener;
import com.google.zxing.client.android.result.ResultHandler;
import com.google.zxing.client.android.result.ResultHandlerFactory;
import com.google.zxing.client.android.share.ShareActivity;

import java.io.IOException;
import java.text.DateFormat;
import java.util.Date;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.Vector;

/**
 * The barcode reader activity itself. This is loosely based on the CameraPreview
 * example included in the Android SDK.
 *
 * @author dswitkin@google.com (Daniel Switkin)
 * @author Sean Owen
 */
public final class CaptureActivity extends Activity implements SurfaceHolder.Callback {

    private static final String TAG = CaptureActivity.class.getSimpleName();
    //menu菜单插入项
    private static final int SHARE_ID = Menu.FIRST;
    private static final int HISTORY_ID = Menu.FIRST + 1;
    private static final int SETTINGS_ID = Menu.FIRST + 2;
    private static final int HELP_ID = Menu.FIRST + 3;
    private static final int ABOUT_ID = Menu.FIRST + 4;

    private static final long INTENT_RESULT_DURATION = 1500L;
    private static final long BULK_MODE_SCAN_DELAY_MS = 1000L;
    private static final float BEEP_VOLUME = 0.10f;
    private static final long VIBRATE_DURATION = 200L;

    private static final String PACKAGE_NAME = "com.google.zxing.client.android";
    private static final String PRODUCT_SEARCH_URL_PREFIX = "http://www.google";
    private static final String PRODUCT_SEARCH_URL_SUFFIX = "/m/products/scan";
    private static final String ZXING_URL = "http://zxing.appspot.com/scan";
    private static final String RETURN_CODE_PLACEHOLDER = "{CODE}";
    private static final String RETURN_URL_PARAM = "ret";

    private static final Set<ResultMetadataType> DISPLAYABLE_METADATA_TYPES;

    static {
        DISPLAYABLE_METADATA_TYPES = new HashSet<ResultMetadataType>(5);
        DISPLAYABLE_METADATA_TYPES.add(ResultMetadataType.ISSUE_NUMBER);
        DISPLAYABLE_METADATA_TYPES.add(ResultMetadataType.SUGGESTED_PRICE);
        DISPLAYABLE_METADATA_TYPES.add(ResultMetadataType.ERROR_CORRECTION_LEVEL);
        DISPLAYABLE_METADATA_TYPES.add(ResultMetadataType.POSSIBLE_COUNTRY);
    }

    private enum Source {
        NATIVE_APP_INTENT,
        PRODUCT_SEARCH_LINK,
        ZXING_LINK,
        NONE
    }

    private CaptureActivityHandler handler;

    private ViewfinderView viewfinderView;
    private TextView statusView;
    private View resultView;
    private MediaPlayer mediaPlayer;
    private Result lastResult;
    private boolean hasSurface;
    private boolean playBeep;
    private boolean vibrate;
    private boolean copyToClipboard;
    private Source source;
    private String sourceUrl;
    private String returnUrlTemplate;
    private Vector<BarcodeFormat> decodeFormats;
    private String characterSet;
    private String versionName;
    private HistoryManager historyManager;
    private InactivityTimer inactivityTimer;

    /**
     * When the beep has finished playing, rewind to queue up another one.
     */
    private final OnCompletionListener beepListener = new OnCompletionListener() {
        public void onCompletion(MediaPlayer mediaPlayer) {
            mediaPlayer.seekTo(0);
        }
    };

    private final DialogInterface.OnClickListener aboutListener =
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialogInterface, int i) {
                    Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(getString(R.string.zxing_url)));
                    intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
                    startActivity(intent);
                }
            };

    ViewfinderView getViewfinderView() {
        return viewfinderView;
    }

    public Handler getHandler() {
        return handler;
    }

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        Window window = getWindow();
        window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
        setContentView(R.layout.capture);
        //初始化 CameraManager
        //这里调用到的 CameraManager 类是控制摄像头的包里的类
        CameraManager.init(getApplication());
        viewfinderView = (ViewfinderView) findViewById(R.id.viewfinder_view);
        resultView = findViewById(R.id.result_view);
        statusView = (TextView) findViewById(R.id.status_view);
        handler = null;
        lastResult = null;
        hasSurface = false;
        historyManager = new HistoryManager(this);
        historyManager.trimHistory();
        inactivityTimer = new InactivityTimer(this);

//    showHelpOnFirstLaunch();
    }

    @Override
    protected void onResume() {
        super.onResume();
        resetStatusView();

        SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view);

        SurfaceHolder surfaceHolder = surfaceView.getHolder();
        if (hasSurface) {
            // The activity was paused but not stopped, so the surface still exists. Therefore
            // surfaceCreated() won't be called, so init the camera here.
            initCamera(surfaceHolder);
        } else {
            // Install the callback and wait for surfaceCreated() to init the camera.
            surfaceHolder.addCallback(this);
            surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        }

        Intent intent = getIntent();
        String action = intent == null ? null : intent.getAction();
        String dataString = intent == null ? null : intent.getDataString();
        if (intent != null && action != null) {
            if (action.equals(Intents.Scan.ACTION)) {
                // Scan the formats the intent requested, and return the result to the calling activity.
                source = Source.NATIVE_APP_INTENT;
                decodeFormats = DecodeFormatManager.parseDecodeFormats(intent);
            } else if (dataString != null && dataString.contains(PRODUCT_SEARCH_URL_PREFIX) &&
                    dataString.contains(PRODUCT_SEARCH_URL_SUFFIX)) {
                // Scan only products and send the result to mobile Product Search.
                source = Source.PRODUCT_SEARCH_LINK;
                sourceUrl = dataString;
                decodeFormats = DecodeFormatManager.PRODUCT_FORMATS;
            } else if (dataString != null && dataString.startsWith(ZXING_URL)) {
                // Scan formats requested in query string (all formats if none specified).
                // If a return URL is specified, send the results there. Otherwise, handle it ourselves.
                source = Source.ZXING_LINK;
                sourceUrl = dataString;
                Uri inputUri = Uri.parse(sourceUrl);
                returnUrlTemplate = inputUri.getQueryParameter(RETURN_URL_PARAM);
                decodeFormats = DecodeFormatManager.parseDecodeFormats(inputUri);
            } else {
                // Scan all formats and handle the results ourselves (launched from Home).
                source = Source.NONE;
                decodeFormats = null;
            }
            characterSet = intent.getStringExtra(Intents.Scan.CHARACTER_SET);
        } else {
            source = Source.NONE;
            decodeFormats = null;
            characterSet = null;
        }

        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
        playBeep = prefs.getBoolean(PreferencesActivity.KEY_PLAY_BEEP, true);
        if (playBeep) {
            // See if sound settings overrides this
            AudioManager audioService = (AudioManager) getSystemService(AUDIO_SERVICE);
            if (audioService.getRingerMode() != AudioManager.RINGER_MODE_NORMAL) {
                playBeep = false;
            }
        }
        vibrate = prefs.getBoolean(PreferencesActivity.KEY_VIBRATE, false);
        copyToClipboard = prefs.getBoolean(PreferencesActivity.KEY_COPY_TO_CLIPBOARD, true);
        initBeepSound();
    }

    @Override
    protected void onPause() {
        super.onPause();
        if (handler != null) {
            handler.quitSynchronously();
            handler = null;
        }
        CameraManager.get().closeDriver();
    }

    @Override
    protected void onDestroy() {
        inactivityTimer.shutdown();
        super.onDestroy();
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            if (source == Source.NATIVE_APP_INTENT) {
                setResult(RESULT_CANCELED);
                finish();
                return true;
            } else if ((source == Source.NONE || source == Source.ZXING_LINK) && lastResult != null) {
                resetStatusView();
                if (handler != null) {
                    handler.sendEmptyMessage(R.id.restart_preview);
                }
                return true;
            }
        } else if (keyCode == KeyEvent.KEYCODE_FOCUS || keyCode == KeyEvent.KEYCODE_CAMERA) {
            // Handle these events so they don't launch the Camera app
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);
        menu.add(0, SHARE_ID, 0, R.string.menu_share)
                .setIcon(android.R.drawable.ic_menu_share);
        menu.add(0, HISTORY_ID, 0, R.string.menu_history)
                .setIcon(android.R.drawable.ic_menu_recent_history);
        menu.add(0, SETTINGS_ID, 0, R.string.menu_settings)
                .setIcon(android.R.drawable.ic_menu_preferences);
        menu.add(0, HELP_ID, 0, R.string.menu_help)
                .setIcon(android.R.drawable.ic_menu_help);
        menu.add(0, ABOUT_ID, 0, R.string.menu_about)
                .setIcon(android.R.drawable.ic_menu_info_details);
        return true;
    }

    // Don't display the share menu item if the result overlay is showing.
    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        super.onPrepareOptionsMenu(menu);
        menu.findItem(SHARE_ID).setVisible(lastResult == null);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case SHARE_ID: {
                Intent intent = new Intent(Intent.ACTION_VIEW);
                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
                intent.setClassName(this, ShareActivity.class.getName());
                startActivity(intent);
                break;
            }
            case HISTORY_ID: {
                AlertDialog historyAlert = historyManager.buildAlert();
                historyAlert.show();
                break;
            }
            case SETTINGS_ID: {
                Intent intent = new Intent(Intent.ACTION_VIEW);
                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
                intent.setClassName(this, PreferencesActivity.class.getName());
                startActivity(intent);
                break;
            }
            case HELP_ID: {
                Intent intent = new Intent(Intent.ACTION_VIEW);
                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
                intent.setClassName(this, HelpActivity.class.getName());
                startActivity(intent);
                break;
            }
            case ABOUT_ID:
                AlertDialog.Builder builder = new AlertDialog.Builder(this);
                builder.setTitle(getString(R.string.title_about) + versionName);
                builder.setMessage(getString(R.string.msg_about) + "\n\n" + getString(R.string.zxing_url));
                builder.setIcon(R.drawable.launcher_icon);
                builder.setPositiveButton(R.string.button_open_browser, aboutListener);
                builder.setNegativeButton(R.string.button_cancel, null);
                builder.show();
                break;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onConfigurationChanged(Configuration config) {
        // Do nothing, this is to prevent the activity from being restarted when the keyboard opens.
        super.onConfigurationChanged(config);
    }

    public void surfaceCreated(SurfaceHolder holder) {
        if (!hasSurface) {
            hasSurface = true;
            //initCamera () 方法用于初始化摄像头
            initCamera(holder);
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        hasSurface = false;
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }

    /**
     * A valid barcode has been found, so give an indication of success and show the results.
     *
     * @param rawResult The contents of the barcode.
     * @param barcode   A greyscale bitmap of the camera data which was decoded.
     */
    //得到的结果存放在rawResult中，
    public void handleDecode(Result rawResult, Bitmap barcode) {
        inactivityTimer.onActivity();
        lastResult = rawResult;
        //new String(rawResult.getBytes("iso-8859-1"),"gb2312");
        historyManager.addHistoryItem(rawResult);
        if (barcode == null) {
            // This is from history -- no saved barcode
            handleDecodeInternally(rawResult, null);
        } else {
            playBeepSoundAndVibrate();
            drawResultPoints(barcode, rawResult);
            switch (source) {
                case NATIVE_APP_INTENT:
                case PRODUCT_SEARCH_LINK:
                    handleDecodeExternally(rawResult, barcode);
                    break;
                case ZXING_LINK:
                    if (returnUrlTemplate == null) {
                        handleDecodeInternally(rawResult, barcode);
                    } else {
                        handleDecodeExternally(rawResult, barcode);
                    }
                    break;
                case NONE:
                    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
                    if (prefs.getBoolean(PreferencesActivity.KEY_BULK_MODE, false)) {
                        Toast.makeText(this, R.string.msg_bulk_mode_scanned, Toast.LENGTH_SHORT).show();
                        // Wait a moment or else it will scan the same barcode continuously about 3 times
                        if (handler != null) {
                            handler.sendEmptyMessageDelayed(R.id.restart_preview, BULK_MODE_SCAN_DELAY_MS);
                        }
                        resetStatusView();
                    } else {
                        handleDecodeInternally(rawResult, barcode);
                    }
                    break;
            }
        }
    }

    /**
     * Superimpose a line for 1D or dots for 2D to highlight the key features of the barcode.
     *
     * @param barcode   A bitmap of the captured image.
     * @param rawResult The decoded results which contains the points to draw.
     */
    private void drawResultPoints(Bitmap barcode, Result rawResult) {
        ResultPoint[] points = rawResult.getResultPoints();
        if (points != null && points.length > 0) {
            Canvas canvas = new Canvas(barcode);
            Paint paint = new Paint();
            paint.setColor(getResources().getColor(R.color.result_image_border));
            paint.setStrokeWidth(3.0f);
            paint.setStyle(Paint.Style.STROKE);
            Rect border = new Rect(2, 2, barcode.getWidth() - 2, barcode.getHeight() - 2);
            canvas.drawRect(border, paint);

            paint.setColor(getResources().getColor(R.color.result_points));
            if (points.length == 2) {
                paint.setStrokeWidth(4.0f);
                drawLine(canvas, paint, points[0], points[1]);
            } else if (points.length == 4 &&
                    (rawResult.getBarcodeFormat().equals(BarcodeFormat.UPC_A)) ||
                    (rawResult.getBarcodeFormat().equals(BarcodeFormat.EAN_13))) {
                // Hacky special case -- draw two lines, for the barcode and metadata
                drawLine(canvas, paint, points[0], points[1]);
                drawLine(canvas, paint, points[2], points[3]);
            } else {
                paint.setStrokeWidth(10.0f);
                for (ResultPoint point : points) {
                    canvas.drawPoint(point.getX(), point.getY(), paint);
                }
            }
        }
    }

    private static void drawLine(Canvas canvas, Paint paint, ResultPoint a, ResultPoint b) {
        canvas.drawLine(a.getX(), a.getY(), b.getX(), b.getY(), paint);
    }

    // Put up our own UI for how to handle the decoded contents.
    private void handleDecodeInternally(Result rawResult, Bitmap barcode) {
        statusView.setVisibility(View.GONE);
        viewfinderView.setVisibility(View.GONE);
        resultView.setVisibility(View.VISIBLE);

        ImageView barcodeImageView = (ImageView) findViewById(R.id.barcode_image_view);
        if (barcode == null) {
            barcodeImageView.setImageBitmap(BitmapFactory.decodeResource(getResources(),
                    R.drawable.launcher_icon));
        } else {
            barcodeImageView.setImageBitmap(barcode);
        }

        TextView formatTextView = (TextView) findViewById(R.id.format_text_view);
        formatTextView.setText(rawResult.getBarcodeFormat().toString());

        ResultHandler resultHandler = ResultHandlerFactory.makeResultHandler(this, rawResult);
        TextView typeTextView = (TextView) findViewById(R.id.type_text_view);
        typeTextView.setText(resultHandler.getType().toString());

        DateFormat formatter = DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT);
        String formattedTime = formatter.format(new Date(rawResult.getTimestamp()));
        TextView timeTextView = (TextView) findViewById(R.id.time_text_view);
        timeTextView.setText(formattedTime);


        TextView metaTextView = (TextView) findViewById(R.id.meta_text_view);
        View metaTextViewLabel = findViewById(R.id.meta_text_view_label);
        metaTextView.setVisibility(View.GONE);
        metaTextViewLabel.setVisibility(View.GONE);
        Map<ResultMetadataType, Object> metadata =
                (Map<ResultMetadataType, Object>) rawResult.getResultMetadata();
        if (metadata != null) {
            StringBuilder metadataText = new StringBuilder(20);
            for (Map.Entry<ResultMetadataType, Object> entry : metadata.entrySet()) {
                if (DISPLAYABLE_METADATA_TYPES.contains(entry.getKey())) {
                    metadataText.append(entry.getValue()).append('\n');
                }
            }
            if (metadataText.length() > 0) {
                metadataText.setLength(metadataText.length() - 1);
                metaTextView.setText(metadataText);
                metaTextView.setVisibility(View.VISIBLE);
                metaTextViewLabel.setVisibility(View.VISIBLE);
            }
        }

        TextView contentsTextView = (TextView) findViewById(R.id.contents_text_view);
        CharSequence displayContents = resultHandler.getDisplayContents();
        contentsTextView.setText(displayContents);
        // Crudely scale betweeen 22 and 32 -- bigger font for shorter text
        int scaledSize = Math.max(22, 32 - displayContents.length() / 4);
        contentsTextView.setTextSize(TypedValue.COMPLEX_UNIT_SP, scaledSize);

        int buttonCount = resultHandler.getButtonCount();
        ViewGroup buttonView = (ViewGroup) findViewById(R.id.result_button_view);
        buttonView.requestFocus();
        for (int x = 0; x < ResultHandler.MAX_BUTTON_COUNT; x++) {
            TextView button = (TextView) buttonView.getChildAt(x);
            if (x < buttonCount) {
                button.setVisibility(View.VISIBLE);
                button.setText(resultHandler.getButtonText(x));
                button.setOnClickListener(new ResultButtonListener(resultHandler, x));
            } else {
                button.setVisibility(View.GONE);
            }
        }

        if (copyToClipboard) {
            ClipboardManager clipboard = (ClipboardManager) getSystemService(CLIPBOARD_SERVICE);
            clipboard.setText(displayContents);
        }
    }

    // Briefly show the contents of the barcode, then handle the result outside Barcode Scanner.
    private void handleDecodeExternally(Result rawResult, Bitmap barcode) {
        viewfinderView.drawResultBitmap(barcode);

        // Since this message will only be shown for a second, just tell the user what kind of
        // barcode was found (e.g. contact info) rather than the full contents, which they won't
        // have time to read.
        ResultHandler resultHandler = ResultHandlerFactory.makeResultHandler(this, rawResult);
        statusView.setText(getString(resultHandler.getDisplayTitle()));

        if (copyToClipboard) {
            ClipboardManager clipboard = (ClipboardManager) getSystemService(CLIPBOARD_SERVICE);
            clipboard.setText(resultHandler.getDisplayContents());
        }

        if (source == Source.NATIVE_APP_INTENT) {
            // Hand back whatever action they requested - this can be changed to Intents.Scan.ACTION when
            // the deprecated intent is retired.
            Intent intent = new Intent(getIntent().getAction());
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
            intent.putExtra(Intents.Scan.RESULT, rawResult.toString());
            intent.putExtra(Intents.Scan.RESULT_FORMAT, rawResult.getBarcodeFormat().toString());
            Message message = Message.obtain(handler, R.id.return_scan_result);
            message.obj = intent;
            handler.sendMessageDelayed(message, INTENT_RESULT_DURATION);
        } else if (source == Source.PRODUCT_SEARCH_LINK) {
            // Reformulate the URL which triggered us into a query, so that the request goes to the same
            // TLD as the scan URL.
            Message message = Message.obtain(handler, R.id.launch_product_query);
            int end = sourceUrl.lastIndexOf("/scan");
            message.obj = sourceUrl.substring(0, end) + "?q=" +
                    resultHandler.getDisplayContents().toString() + "&source=zxing";
            handler.sendMessageDelayed(message, INTENT_RESULT_DURATION);
        } else if (source == Source.ZXING_LINK) {
            // Replace each occurrence of RETURN_CODE_PLACEHOLDER in the returnUrlTemplate
            // with the scanned code. This allows both queries and REST-style URLs to work.
            Message message = Message.obtain(handler, R.id.launch_product_query);
            message.obj = returnUrlTemplate.replace(RETURN_CODE_PLACEHOLDER,
                    resultHandler.getDisplayContents().toString());
            handler.sendMessageDelayed(message, INTENT_RESULT_DURATION);
        }
    }

    /**
     * We want the help screen to be shown automatically the first time a new version of the app is
     * run. The easiest way to do this is to check android:versionCode from the manifest, and compare
     * it to a value stored as a preference.
     */
    private boolean showHelpOnFirstLaunch() {
        try {
            PackageInfo info = getPackageManager().getPackageInfo(PACKAGE_NAME, 0);
            int currentVersion = info.versionCode;
            // Since we're paying to talk to the PackageManager anyway, it makes sense to cache the app
            // version name here for display in the about box later.
            this.versionName = info.versionName;
            SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
            int lastVersion = prefs.getInt(PreferencesActivity.KEY_HELP_VERSION_SHOWN, 0);
            if (currentVersion > lastVersion) {
                prefs.edit().putInt(PreferencesActivity.KEY_HELP_VERSION_SHOWN, currentVersion).commit();
                Intent intent = new Intent(this, HelpActivity.class);
                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
                // Show the default page on a clean install, and the what's new page on an upgrade.
                String page = (lastVersion == 0) ? HelpActivity.DEFAULT_PAGE : HelpActivity.WHATS_NEW_PAGE;
                intent.putExtra(HelpActivity.REQUESTED_PAGE_KEY, page);
                startActivity(intent);
                return true;
            }
        } catch (PackageManager.NameNotFoundException e) {
            Log.w(TAG, e);
        }
        return false;
    }

    /**
     * Creates the beep MediaPlayer in advance so that the sound can be triggered with the least
     * latency possible.
     */
    private void initBeepSound() {
        if (playBeep && mediaPlayer == null) {
            // The volume on STREAM_SYSTEM is not adjustable, and users found it too loud,
            // so we now play on the music stream.
            setVolumeControlStream(AudioManager.STREAM_MUSIC);
            mediaPlayer = new MediaPlayer();
            mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
            mediaPlayer.setOnCompletionListener(beepListener);

            AssetFileDescriptor file = getResources().openRawResourceFd(R.raw.beep);
            try {
                mediaPlayer.setDataSource(file.getFileDescriptor(), file.getStartOffset(),
                        file.getLength());
                file.close();
                mediaPlayer.setVolume(BEEP_VOLUME, BEEP_VOLUME);
                mediaPlayer.prepare();
            } catch (IOException e) {
                mediaPlayer = null;
            }
        }
    }

    private void playBeepSoundAndVibrate() {
        if (playBeep && mediaPlayer != null) {
            mediaPlayer.start();
        }
        if (vibrate) {
            Vibrator vibrator = (Vibrator) getSystemService(VIBRATOR_SERVICE);
            vibrator.vibrate(VIBRATE_DURATION);
        }
    }

    private void initCamera(SurfaceHolder surfaceHolder) {
        try {
            CameraManager.get().openDriver(surfaceHolder);
        } catch (IOException ioe) {
            Log.w(TAG, ioe);
            displayFrameworkBugMessageAndExit();
            return;
        } catch (RuntimeException e) {
            // Barcode Scanner has seen crashes in the wild of this variety:
            // java.?lang.?RuntimeException: Fail to connect to camera service
            Log.w(TAG, "Unexpected error initializating camera", e);
            displayFrameworkBugMessageAndExit();
            return;
        }
        if (handler == null) {
            handler = new CaptureActivityHandler(this, decodeFormats, characterSet);
        }
    }

    private void displayFrameworkBugMessageAndExit() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle(getString(R.string.app_name));
        builder.setMessage(getString(R.string.msg_camera_framework_bug));
        builder.setPositiveButton(R.string.button_ok, new FinishListener(this));
        builder.setOnCancelListener(new FinishListener(this));
        builder.show();
    }

    private void resetStatusView() {
        resultView.setVisibility(View.GONE);
        statusView.setText(R.string.msg_default_status);
        statusView.setVisibility(View.VISIBLE);
        viewfinderView.setVisibility(View.VISIBLE);
        lastResult = null;
    }

    public void drawViewfinder() {
        viewfinderView.drawViewfinder();
    }
}
